This invention relates to a device for forming a tactilely readable display including Braille characters. More particularly, the invention relates to such a Braille reading device which has a planar display carrier with raised raster dots formed by spherical segments protruding selectively through openings in the surface of the display carrier.
The Braille format comprises a combination of 6 and 8 tactilely detectable raster dots which are arranged in a rectangular array, i.e., below one another and side by side. The raster is further characterized by different raster dot spacings. For Braille reading devices with key buttons, the "Marburg System Large," which has a Braille raster of 2.7 mm., is particularly suitable.
Known electromagnetically operable Braille reading devices of the above-described general type are provided with an indicctor or reading panel which has a hole raster with the basic Braille character configuration. In the holes are disposed pins which are upwardly movable independently of one another by means of electromagnets, the totality of the outwardly protruding pins forming a tactilely readable display including Braille characters. In one of the known Braille reading devices, the outwardly protruding pin ends take the form of spherical segments. In all of the conventional devices the size of the text which can be presented at one time is limited by the size of the display panel. If a single text cannot be accommodated on the display panel, the text must be subdivided into sections and stored, the stored text sections being converted into electrical signals.
As described in U.S. Pat. No. 3,987,438, a Braille reading device includes for each key button two magnets arranged one below the other at least in the axial direction, one or both of the magnets being designed as electromagnets. Through electrical excitation, the magnets generate a force in the axial direction of the key button. This force raises or lowers the key button by means of a magnet coil in accordance with the direction of excitation. For each key button a mechanical, magnetically controlled latching device is provided which acts only on the respective key button. The adaptation of such a Braille reading device to provide a graphic display as well as a display of Braille alphabet characters requires a large number of key buttons and a correspondingly large amount of mechanical actuating means.
An object of the present invention is to provide an improved device for forming a tactile display, including Braille characters, of the above-described general type.
Another, more particular, object of the present invention is to provide such a Braille reading device which enables a pictorial or graphic display, as well as a display of several lines of Braille characters.
Another particular object of the present invention is to provide such a Braille reading device in which the display can be copied onto a tangible storage medium.
Yet another particular object of the present invention is to provide such a Braille reading device which is capable of programming and interrogation functions.
Yet another specific object of the present invention is to provide a simplified Braille reading device of the above-described general type which has a relatively reduced number of components.